[21.17] Soft X-Ray Spectra and Light Curves of Cataclysmic Variables

We report on spectral and temporal analysis of the pointed ROSAT
observations of a dozen cataclysmic variables. All the sufficiently
strong sources show rapid aperiodic variations (``flickering") but
no definite periods were found. Limits on the pulsed fraction of two
DQ~Her star candidates (TW~Pic and TT~Ari) were found to be $\sim$~30\%.
The stars at high binary inclination (IP~Peg, V2051~Oph, V347~Pup, V~Sge,
and H0928+50) were found to be very feeble X-ray sources, presumably
because of X-ray absorption in the accretion disk. A search for X-ray
eclipses was basically negative, although this result is tainted by the
very low count rates. Orbital modulations in the X-ray hardness ratio
were found or suspected in three stars (RXJ1940.2-1025, WZ~Sge, and GP~Com),
suggesting the possibility of X-ray absorption in an orbital structure
(accretion column, accretion stream, or hot spot at the outer edge of the
disk). Better orbital ephemerides and/or modelling of the physics and
geometry of the X-ray absorption are needed to evaluate this possibility.